Diamond Nanoparticles-Porphyrin mTHPP Conjugate as Photosensitizing Platform: Cytotoxicity and Antibacterial Activity

• Published in: Nanomaterials (Basel, Switzerland) Vol. 11; no. 6; p. 1393
• Main Authors: Hurtado, Carolina Ramos, Hurtado, Gabriela Ramos, Cena, Gabrielle Lupeti de, Queiroz, Rafaela Campos, Silva, Alexandre Vieira, Diniz, Milton Faria, Santos, Verônica Ribeiro Dos, Trava-Airoldi, Vladimir, Baptista, Maurício da Silva, Tsolekile, Ncediwe, Oluwafemi, Oluwatobi Samuel, Conceição, Katia, Tada, Dayane Batista
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 25.05.2021; MDPI
• Subjects: Ampicillin; Antibacterial activity; Antibiotics; Antimicrobial activity; Antimicrobial agents; Bacteria; Biological effects; Cancer; Cavitation; Cell walls; Chemical vapor deposition; Conjugation; Covalent bonds; Cytotoxicity; Diamonds; Drug resistance; E coli; Efficiency; Embryo fibroblasts; Growth inhibition; Irradiation; Microorganisms; nanoconjugate; Nanomaterials; Nanoparticles; Particle size; Peptides; photodynamic antimicrobial therapy (aPDT); Photodynamic therapy; Photosensitization; photosensitizers (PS); Porphyrins; Radiation; Toxicity; Zeta potential; Brazil; United States > US; drug-resistance; photosensitizers (PS); photodynamic antimicrobial therapy (aPDT); nanoconjugate
• ISSN: 2079-4991; 2079-4991
• DOI: 10.3390/nano11061393

Conjugation of photosensitizers (PS) with nanoparticles has been largely used as a strategy to stabilize PS in the biological medium resulting in photosensitizing nanoparticles of enhanced photoactivity. Herein, (Meso-5, 10, 15, 20-tetrakis (3-hydroxyphenyl) phorphyryn (mTHPP) was conjugated with diamond nanoparticles (ND) by covalent bond. Nanoconjugate ND-mTHPP showed suitable stability in aqueous suspension with 58 nm of hydrodynamic diameter and Zeta potential of -23 mV. The antibacterial activity of ND-mTHPP was evaluated against for different incubation times (0-24 h). The optimal activity was observed after 2 h of incubation and irradiation (660 nm; 51 J/cm ) performed right after the addition of ND-mTHPP (100 μg/mL) to the bacterial suspension. The inhibitory activity was 56% whereas ampicillin at the same conditions provided only 14% of bacterial growth inhibition. SEM images showed agglomerate of ND-mTHPP adsorbed on the bacterial cell wall, suggesting that the antimicrobial activity of ND-mTHPP was afforded by inducing membrane damage. Cytotoxicity against murine embryonic fibroblast cells (MEF) was also evaluated and ND-mTHPP was shown to be noncytotoxic since viability of cells cultured for 24 h in the presence of the nanoconjugate (100 μg/mL) was 78%. Considering the enhanced antibacterial activity and the absence of cytotoxic effect, it is possible to consider the ND-mTHPP nanoconjugate as promising platform for application in antimicrobial photodynamic therapy (aPDT).